Condensate management systems and methods

ABSTRACT

The present disclosure relates to present disclosure relates to a heating and cooling system having a duct liner configured to be disposed within an air duct and at least partially downstream of a heat exchanger coil relative to a direction of airflow within the air duct. The duct liner includes a tube and is configured to flow fluid from the heat exchanger coil toward a drain of the heating and cooling system.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Non-Provisional Application claiming priority to U.S. Provisional Application No. 62/682,026, entitled “CONDENSATE MANAGEMENT SYSTEMS AND METHODS,” filed Jun. 7, 2018, which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND

The present disclosure relates generally to heating, ventilation, and air conditioning systems. A wide range of applications exist for heating, ventilation, and air conditioning (HVAC) systems. For example, residential, light commercial, commercial, and industrial systems are used to control temperatures and air quality in residences and buildings. Such systems often are dedicated to either heating or cooling, although systems are common that perform both of these functions. Very generally, these systems operate by implementing a thermal cycle in which fluids are heated and cooled to provide the desired temperature in a controlled space, typically the inside of a residence or building. Similar systems are used for vehicle heating and cooling, and as well as for general refrigeration. In many HVAC systems, a drain pan may be utilized to collect condensate from a heat exchanger coil.

SUMMARY

The present disclosure relates to a heating and cooling system having a duct liner configured to be disposed within an air duct and at least partially downstream of a heat exchanger coil relative to a direction of airflow within the air duct. The duct liner includes a tube and is configured to flow fluid from the heat exchanger coil toward a drain of the heating and cooling system.

The present disclosure also relates to a heat exchanger system having an evaporator coil configured to condense a vapor within air flowing through the heat exchanger system. The heat exchanger system further includes a duct liner configured to encircle the evaporator coil and extend downstream of the evaporator coil. The duct liner is also configured to guide condensate from the vapor toward a drain of the heat exchanger system.

The present disclosure further relates to a heating and cooling system having a duct configured to flow air in a downstream direction. The duct includes a heat exchanger coil and a drain pan configured to surround the heat exchanger coil. The drain pan is also configured to guide condensate from the air to a drain of the heating and cooling system.

DRAWINGS

FIG. 1 is a perspective view of an embodiment of a heating, ventilation, and air conditioning (HVAC) system for building environmental management that may employ one or more HVAC units, in accordance with aspects of the present disclosure;

FIG. 2 is a perspective view of an embodiment of an HVAC unit of the HVAC system of FIG. 1, in accordance with aspects of the present disclosure;

FIG. 3 is a perspective view of an embodiment of a residential split heating and cooling system, in accordance with aspects of the present disclosure;

FIG. 4 is a schematic view of an embodiment of a vapor compression system that may be used in an HVAC system, in accordance with aspects of the present disclosure;

FIG. 5 is a cross-sectional perspective view of an embodiment of a portion of a duct that may utilize a duct liner; in accordance with aspects of the present disclosure;

FIG. 6 is a cross-sectional perspective view of an embodiment of a portion of a duct that may utilize the duct liner of FIG. 5; in accordance with aspects of the present disclosure;

FIG. 7 is a perspective view of an embodiment of the duct liner of FIG. 5, in accordance with aspects of the present disclosure;

FIG. 8 is a perspective view of an embodiment of the duct liner of FIG. 5, in accordance with aspects of the present disclosure; and

FIG. 9 is a perspective view of an embodiment of the duct liner of FIG. 5, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to heating, ventilation, and air conditioning (HVAC) systems that may include a duct liner utilized to collect condensate that may be blown from evaporator coils or other heat exchanger. For example, in some instances, a drain pan may be utilized to collect condensate that drips downward from an evaporator coil. As will be appreciated, a portion of condensate may be blown or drawn downstream of traditional drain pans, and as such, may not be collected by a traditional drain pan. Accordingly, the disclosed embodiments include a duct liner configured to collect condensate that may be blown or drawn further downstream of the evaporator coil. For example, unlike traditional drain pans which may be placed only directly or substantially directly beneath the evaporator coil, the presently disclosed embodiments include a duct liner that may extend downstream beyond the evaporator coil within an airflow path of the HVAC system. As such, the disclosed embodiments may reduce the amount of condensate that may be leaked into other portions of the system by collecting condensate that is blown downstream of the evaporator coil.

Turning now to the drawings, FIG. 1 illustrates a heating, ventilation, and air conditioning (HVAC) system for building environmental management that may employ one or more HVAC units. In the illustrated embodiment, a building 10 is air conditioned by a system that includes an HVAC unit 12. The building 10 may be a commercial structure or a residential structure. As shown, the HVAC unit 12 is disposed on the roof of the building 10; however, the HVAC unit 12 may be located in other equipment rooms or areas adjacent the building 10. The HVAC unit 12 may be a single package unit containing other equipment, such as a blower, integrated air handler, and/or auxiliary heating unit. In other embodiments, the HVAC unit 12 may be part of a split HVAC system, such as the system shown in FIG. 3, which includes an outdoor HVAC unit 58 and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigeration cycle to provide conditioned air to the building 10. Specifically, the HVAC unit 12 may include one or more heat exchangers across which an air flow is passed to condition the air flow before the air flow is supplied to the building. In the illustrated embodiment, the HVAC unit 12 is a rooftop unit (RTU) that conditions a supply air stream, such as environmental air and/or a return air flow from the building 10. After the HVAC unit 12 conditions the air, the air is supplied to the building 10 via ductwork 14 extending throughout the building 10 from the HVAC unit 12. For example, the ductwork 14 may extend to various individual floors or other sections of the building 10. In certain embodiments, the HVAC unit 12 may be a heat pump that provides both heating and cooling to the building with one refrigeration circuit configured to operate in different modes. In other embodiments, the HVAC unit 12 may include one or more refrigeration circuits for cooling an air stream and a furnace for heating the air stream.

A control device 16, one type of which may be a thermostat, may be used to designate the temperature of the conditioned air. The control device 16 also may be used to control the flow of air through the ductwork 14. For example, the control device 16 may be used to regulate operation of one or more components of the HVAC unit 12 or other components, such as dampers and fans, within the building 10 that may control flow of air through and/or from the ductwork 14. In some embodiments, other devices may be included in the system, such as pressure and/or temperature transducers or switches that sense the temperatures and pressures of the supply air, return air, and so forth. Moreover, the control device 16 may include computer systems that are integrated with or separate from other building control or monitoring systems, and even systems that are remote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. In the illustrated embodiment, the HVAC unit 12 is a single package unit that may include one or more independent refrigeration circuits and components that are tested, charged, wired, piped, and ready for installation. The HVAC unit 12 may provide a variety of heating and/or cooling functions, such as cooling only, heating only, cooling with electric heat, cooling with dehumidification, cooling with gas heat, or cooling with a heat pump. As described above, the HVAC unit 12 may directly cool and/or heat an air stream provided to the building 10 to condition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2, a cabinet 24 encloses the HVAC unit 12 and provides structural support and protection to the internal components from environmental and other contaminants. In some embodiments, the cabinet 24 may be constructed of galvanized steel and insulated with aluminum foil faced insulation. Rails 26 may be joined to the bottom perimeter of the cabinet 24 and provide a foundation for the HVAC unit 12. In certain embodiments, the rails 26 may provide access for a forklift and/or overhead rigging to facilitate installation and/or removal of the HVAC unit 12. In some embodiments, the rails 26 may fit into “curbs” on the roof to enable the HVAC unit 12 to provide air to the ductwork 14 from the bottom of the HVAC unit 12 while blocking elements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluid communication with one or more refrigeration circuits. Tubes within the heat exchangers 28 and 30 may circulate refrigerant, such as R-410A, through the heat exchangers 28 and 30. The tubes may be of various types, such as multichannel tubes, conventional copper or aluminum tubing, and so forth. Together, the heat exchangers 28 and 30 may implement a thermal cycle in which the refrigerant undergoes phase changes and/or temperature changes as it flows through the heat exchangers 28 and 30 to produce heated and/or cooled air. For example, the heat exchanger 28 may function as a condenser where heat is released from the refrigerant to ambient air, and the heat exchanger 30 may function as an evaporator where the refrigerant absorbs heat to cool an air stream. In other embodiments, the HVAC unit 12 may operate in a heat pump mode where the roles of the heat exchangers 28 and 30 may be reversed. That is, the heat exchanger 28 may function as an evaporator and the heat exchanger 30 may function as a condenser. In further embodiments, the HVAC unit 12 may include a furnace for heating the air stream that is supplied to the building 10. While the illustrated embodiment of FIG. 2 shows the HVAC unit 12 having two of the heat exchangers 28 and 30, in other embodiments, the HVAC unit 12 may include one heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separates the heat exchanger 30 from the heat exchanger 28. Fans 32 draw air from the environment through the heat exchanger 28. Air may be heated and/or cooled as the air flows through the heat exchanger 28 before being released back to the environment surrounding the rooftop unit 12. A blower assembly 34, powered by a motor 36, draws air through the heat exchanger 30 to heat or cool the air. The heated or cooled air may be directed to the building 10 by the ductwork 14, which may be connected to the HVAC unit 12. Before flowing through the heat exchanger 30, the conditioned air flows through one or more filters 38 that may remove particulates and contaminants from the air. In certain embodiments, the filters 38 may be disposed on the air intake side of the heat exchanger 30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing the thermal cycle. Compressors 42 increase the pressure and temperature of the refrigerant before the refrigerant enters the heat exchanger 28. The compressors 42 may be any suitable type of compressors, such as scroll compressors, rotary compressors, screw compressors, or reciprocating compressors. In some embodiments, the compressors 42 may include a pair of hermetic direct drive compressors arranged in a dual stage configuration 44. However, in other embodiments, any number of the compressors 42 may be provided to achieve various stages of heating and/or cooling. As may be appreciated, additional equipment and devices may be included in the HVAC unit 12, such as a solid-core filter drier, a drain pan, a disconnect switch, an economizer, pressure switches, phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. For example, a high voltage power source may be connected to the terminal block 46 to power the equipment. The operation of the HVAC unit 12 may be governed or regulated by a control board 48. The control board 48 may include control circuitry connected to a thermostat, sensors, and alarms. One or more of these components may be referred to herein separately or collectively as the control device 16. The control circuitry may be configured to control operation of the equipment, provide alarms, and monitor safety switches. Wiring 49 may connect the control board 48 and the terminal block 46 to the equipment of the HVAC unit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also in accordance with present techniques. The residential heating and cooling system 50 may provide heated and cooled air to a residential structure, as well as provide outside air for ventilation and provide improved indoor air quality (IAQ) through devices such as ultraviolet lights and air filters. In the illustrated embodiment, the residential heating and cooling system 50 is a split HVAC system. In general, a residence 52 conditioned by a split HVAC system may include refrigerant conduits 54 that operatively couple the indoor unit 56 to the outdoor unit 58. The indoor unit 56 may be positioned in a utility room, an attic, a basement, and so forth. The outdoor unit 58 is typically situated adjacent to a side of residence 52 and is covered by a shroud to protect the system components and to prevent leaves and other debris or contaminants from entering the unit. The refrigerant conduits 54 transfer refrigerant between the indoor unit 56 and the outdoor unit 58, typically transferring primarily liquid refrigerant in one direction and primarily vaporized refrigerant in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, a heat exchanger 60 in the outdoor unit 58 serves as a condenser for re-condensing vaporized refrigerant flowing from the indoor unit 56 to the outdoor unit 58 via one of the refrigerant conduits 54. In these applications, a heat exchanger 62 of the indoor unit functions as an evaporator. Specifically, the heat exchanger 62 receives liquid refrigerant, which may be expanded by an expansion device, and evaporates the refrigerant before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger 60 using a fan 64 and expels the air above the outdoor unit 58. When operating as an air conditioner, the air is heated by the heat exchanger 60 within the outdoor unit 58 and exits the unit at a temperature higher than it entered. The indoor unit 56 includes a blower or fan 66 that directs air through or across the indoor heat exchanger 62, where the air is cooled when the system is operating in air conditioning mode. Thereafter, the air is passed through ductwork 68 that directs the air to the residence 52. The overall system operates to maintain a desired temperature as set by a system controller. When the temperature sensed inside the residence 52 is higher than the set point on the thermostat, or the set point plus a small amount, the residential heating and cooling system 50 may become operative to refrigerate additional air for circulation through the residence 52. When the temperature reaches the set point, or the set point minus a small amount, the residential heating and cooling system 50 may stop the refrigeration cycle temporarily.

The residential heating and cooling system 50 may also operate as a heat pump. When operating as a heat pump, the roles of heat exchangers 60 and 62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58 will serve as an evaporator to evaporate refrigerant and thereby cool air entering the outdoor unit 58 as the air passes over outdoor the heat exchanger 60. The indoor heat exchanger 62 will receive a stream of air blown over it and will heat the air by condensing the refrigerant.

In some embodiments, the indoor unit 56 may include a furnace system 70. For example, the indoor unit 56 may include the furnace system 70 when the residential heating and cooling system 50 is not configured to operate as a heat pump. The furnace system 70 may include a burner assembly and heat exchanger, among other components, inside the indoor unit 56. Fuel is provided to the burner assembly of the furnace 70 where it is mixed with air and combusted to form combustion products. The combustion products may pass through tubes or piping in a heat exchanger, separate from heat exchanger 62, such that air directed by the blower 66 passes over the tubes or pipes and extracts heat from the combustion products. The heated air may then be routed from the furnace system 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can be used in any of the systems described above. The vapor compression system 72 may circulate a refrigerant through a circuit starting with a compressor 74. The circuit may also include a condenser 76, an expansion valve(s) or device(s) 78, and an evaporator 80. The vapor compression system 72 may further include a control panel 82 that has an analog to digital (A/D) converter 84, a microprocessor 86, a non-volatile memory 88, and/or an interface board 90. The control panel 82 and its components may function to regulate operation of the vapor compression system 72 based on feedback from an operator, from sensors of the vapor compression system 72 that detect operating conditions, and so forth.

In some embodiments, the vapor compression system 72 may use one or more of a variable speed drive (VSDs) 92, a motor 94, the compressor 74, the condenser 76, the expansion valve or device 78, and/or the evaporator 80. The motor 94 may drive the compressor 74 and may be powered by the variable speed drive (VSD) 92. The VSD 92 receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 94. In other embodiments, the motor 94 may be powered directly from an AC or direct current (DC) power source. The motor 94 may include any type of electric motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

The compressor 74 compresses a refrigerant vapor and delivers the vapor to the condenser 76 through a discharge passage. In some embodiments, the compressor 74 may be a centrifugal compressor. The refrigerant vapor delivered by the compressor 74 to the condenser 76 may transfer heat to a fluid passing across the condenser 76, such as ambient or environmental air 96. The refrigerant vapor may condense to a refrigerant liquid in the condenser 76 as a result of thermal heat transfer with the environmental air 96. The liquid refrigerant from the condenser 76 may flow through the expansion device 78 to the evaporator 80.

The liquid refrigerant delivered to the evaporator 80 may absorb heat from another air stream, such as a supply air stream 98 provided to the building 10 or the residence 52. For example, the supply air stream 98 may include ambient or environmental air, return air from a building, or a combination of the two. The liquid refrigerant in the evaporator 80 may undergo a phase change from the liquid refrigerant to a refrigerant vapor. In this manner, the evaporator 38 may reduce the temperature of the supply air stream 98 via thermal heat transfer with the refrigerant. Thereafter, the vapor refrigerant exits the evaporator 80 and returns to the compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further include a reheat coil in addition to the evaporator 80. For example, the reheat coil may be positioned downstream of the evaporator relative to the supply air stream 98 and may reheat the supply air stream 98 when the supply air stream 98 is overcooled to remove humidity from the supply air stream 98 before the supply air stream 98 is directed to the building 10 or the residence 52.

It should be appreciated that any of the features described herein may be incorporated with the HVAC unit 12, the residential heating and cooling system 50, or other HVAC systems. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well. For example, the features described herein may be applied to mechanical cooling systems, free cooling systems, chiller systems, or other heat pump or refrigeration applications.

As discussed below, an HVAC system, such as the HVAC unit 12, the residential heating and cooling system 50, and/or the vapor compression system 72, may utilize a heat exchanger, such as the heat exchanger 28, the heat exchanger 60, the heat exchanger 62, and/or the evaporator 80. The HVAC system may further utilize a drain pan positioned below a heat exchanger coil to collect condensate that falls from the heat exchanger coil. In some embodiments, the condensate may be pushed or pulled beyond the drain pan due at least in part to an air mover. Accordingly, the HVAC system may further include a duct liner positioned downstream of the drain pan to collect the condensate that is blown downstream of the drain pan. For example, the duct liner may be positioned vertically above the drain pan such that, as the condensate is blown from the coil to an area beyond or downstream from the drain pan, the condensate may impinge the duct liner and flow to the drain pan. Accordingly, the duct liner may reduce the amount of condensate that may be blown to other portions of the HVAC system.

To illustrate, FIG. 5 is a schematic view of a heat exchanger 100 within a duct 102 of an HVAC system 104. Indeed, the heat exchanger 100 may be an evaporator heat exchanger that is configured to receive chilled refrigerant or other liquid through coils 106 to condense, cool, and/or dehumidify air 108 that is moved across the coils 106. In some embodiments, the coils 106 may be positioned within coil slabs 107. Particularly, the air 108 may be pulled or forced across the coils 106 by an air mover 110, such as a fan or a blower. As shown in the illustrated embodiment, the air mover 110 is positioned downstream 112 of the coils 106 to pull the air 108 across the coils 106. However, it should be noted that, in some embodiments, the air mover 110 may be positioned upstream 114 of the coils 106 to push the air across the coils 106. Moreover, as discussed herein, positions of various elements of the disclosed embodiments may be referenced as downstream 112 and/or upstream 114 relative to other elements. The downstream 112 and upstream 114 directions are expressed relative to the direction of flow of the air 108 through the duct 102. Further, as discussed herein, positions of various elements of the disclosed embodiments may be referenced as vertically 113 or horizontally 115 positioned relative to other elements. The vertical 113 and horizontal 115 directions are expressed relative to the direction of gravity. That is, the vertical 113 direction may be substantially parallel with the direction of gravity and the horizontal 115 direction may be substantially perpendicular with the direction of gravity.

As the air 108 moves across the coils 106, moisture or water within the air 108 may condense and gather about the coils 106. As the water from the air 108 continues to condense, the condensate or condensed water may drop to a drain pan 130 positioned vertically below the coils 106. The condensate may then flow to a drain 132 to flow to an external location, as shown by arrows 133. As discussed above, in some embodiments, the condensate gathered about the coils 106 may fall beyond, or downstream 112, of the drain pan 130. Indeed, as shown, a downstream end 134 of the drain pan 130 may extend merely a short distance beyond of a downstream end 135 of the coils 106, or may not extend beyond the downstream end 134 of the coils 106. Indeed, in certain embodiments, the downstream end 134 of the drain pan 130 may be substantially even with the downstream end 135 of the coils 106 relative to the downstream direction 112.

As mentioned above, in certain embodiments, the air mover 110 may pull the condensate from the coils 106 to fall downstream 112 of the drain pan 130. In other words, the air mover 110 may blow or draw the condensate off of the coils 106, such that the condensate has some lateral movement in addition to the downward movement caused by gravity, as shown by arrow 139. Accordingly, the duct 102 may include a duct liner 140 positioned downstream 112 of the coils 106. Particularly, in certain embodiments, the duct liner 140 may extend approximately 12 inches, 18 inches, or between 12 and 18 inches downstream 112 of the drain pan 130. In other embodiments, the duct liner 140 may extend other distances from the drain pain 130 in the downstream 112 direction.

In some embodiments, the distance to which the duct liner 140 extends downstream 112 of the coils 106 may be based on an airflow speed of the air 108. In this manner, as the condensate falls downstream 112 of the drain pan 130, the condensate may impinge the duct liner 140 and flow upstream 114 to the drain pan 130 into the drain 132, as shown by arrows 137. Moreover, at least to promote a flow of water from the duct liner 140 to the drain pan 130, the duct liner 140 may be positioned vertically 113 above drain pan 130. In some embodiments, the duct liner 140 may replace the drain pan 130. That is, the duct liner 140 may extend from the drain 132 to approximately between 12 and 18 inches downstream 112 of the coils 106.

Further, as discussed in detail below, the duct liner 140 may be generally angled downward toward the drain pan 130 to help the condensate flow towards the drain pan 130. More specifically, a bottom surface 141 of the duct liner 140 may be angled downward toward the drain 132. For example, an angle 143 of the bottom surface 141 of the duct liner 140 relative to a horizontal plane 145 may be approximately 1 to 2 degrees, 1 to 5 degrees, or 1 to 10 degrees. Indeed, in certain embodiments, the duct liner 140 may maintain a substantially constant cross-sectional shape/curvature along a length 147 of the duct liner 140. For example, the duct liner 140 may be a hollow rectangular prism or a hollow cylinder. In other embodiments, the duct liner 140 may be conical or pyramidal in shape at least in part to provide the angle 143. Moreover, in certain embodiments, a top surface 149 of the duct liner 140 may be disposed substantially horizontally 115 while the bottom surface 141 of the duct liner 140 may be disposed at the angle 143 relative to the horizontal plane 145.

In certain embodiments, an interface 142 between the duct liner 140 and the drain pan 130 may include a seal 144 to help block or obstruct water from traveling into the interface 142. In some embodiments, the seal 144 may include welding, brazing, bolting, caulking, seal inserts (rubber, plastic, or metal), or any other suitable type of seal 144. Further, the duct liner 140 may be coupled to the duct 102 via welding, brazing, bolting, or any other suitable manner. In some embodiments, the duct liner 140 may not be coupled to drain pan 130 and may simply rest atop and/or be supported in the vertical direction 113 by the drain pan 130. In some embodiments, the duct liner 140 may be disposed some distance vertically 113 above the drain pan 130. Moreover, in certain embodiments, the duct liner 140 may be supported in the vertical direction by a riser 146 disposed between an interior surface 150 of the duct 102 and the duct liner 140. The riser 146 may increase an elevation of a downstream end 152 of the duct liner 140 to promote the flow of water from the duct liner 140 to the drain pan 130, as discussed above.

As shown, the duct liner 140 may be disposed adjacent to the interior surface 150 of the duct 102. For example, in certain embodiments the duct liner 140 may substantially match the shape, or curvature, of the interior surface 150. Indeed, the duct liner 140 may be rectilinear in shape if the duct 102 has rectilinear cross section or may be curvilinear, or circular in shape, if the duct 102 has a curvilinear cross section. In some embodiments, a first cabinet 152 of the duct 102 that includes the coils 106 may have a first shape, such as rectilinear, and a second cabinet 154 of the duct 102 may have a second shape, such as curvilinear. In such embodiments, a first portion 156 of the duct liner 102 corresponding to the first cabinet 152 may match the curvature of the first cabinet 152, such as rectilinear while a second portion 158 of the duct liner 102 corresponding to the second cabinet 154 may match the curvature of the second cabinet 154, such as curvilinear. In this manner, the duct liner 140 may maintain the mass air flow rate of the duct 102 by substantially maintaining the available cross sectional area of the interior surface 150 of the duct 102 through which the air 108 flows. In some embodiments, the shape of the duct liner 140 may be configured to promote airflow through the duct 102.

In certain embodiments, the duct liner 140 may be disposed a distance away from the interior surface 150 of the duct 102, such that a gap 170 is disposed between the duct liner 140 and the interior surface 150 of the duct 102. The gap 170 may be approximately 0.1 inches, 0.5 inches, 1 inch, 2 inches, 5 inches, or any other suitable dimension in length. For example, as discussed above, the duct liner 140 may be disposed at the angle 143 to promote the flow of condensate along the duct liner 140 toward the drain 132. Accordingly, as shown, in certain embodiments, the gap 170 disposed vertically 113 above the duct liner 140 may be lesser in length than the gap 170 disposed vertically 113 below the duct liner 140.

In some embodiments, the gap 170 disposed between the duct liner 140 and the interior surface 150 of the duct 102 may provide thermal insulation between the air 108 moving through the duct 102 and an external environment 172 of the duct 102, such as an attic space. Particularly, the gap 170 may include air, which may act as a thermal insulator, such that an amount of heat that is transferred between the air 108 and the external environment 172 is reduced, which may increase an efficiency of the HVAC system 104. In some embodiments, the gap 170 may be sealed and vacuum insulated. Moreover, in certain embodiments, the interior surface 150 of the duct may be lined with an insulator, such as a fiber glass insulation with a metallic surface facing the duct liner 140.

Additionally, in some embodiments, the duct liner 140 may include a lip 180 disposed at the downstream end 152 of the duct liner 140. Particularly, the lip 180 may extend inward, such as radially inward, from the inner surface of the duct liner 140 at, or adjacent to, an edge 182 of the downstream end 152 of the duct liner 140. In some embodiments, the lip 180 may be disposed about a bottom portion 184 of the edge 180. Further, in some embodiments, the lip 180 may be disposed about the entirety of the edge 180. Generally, the lip 180 may reduce the potential for condensate to move or travel downstream 112 beyond the duct liner 140. Indeed, in some embodiments, the air mover 110 may push or pull the condensate that has gathered/impinged on the duct liner 140 to move downstream 112 along the duct liner 140. Accordingly, the lip 180 may block the condensate from flowing downstream 112 beyond the duct liner 140.

As shown, the duct liner 140 may surround, or encircle, a downstream 112 portion of the coils 106. Particularly, the duct liner 140 may be configured to encircle the coils 106 such that the duct liner 140 completely surrounds the coils 106 in at least one vertical plane. That is, the duct liner 140 may include an opening in which the coils 106 may be disposed such that the duct liner 140 radially surrounds, or encircles, a portion of the coils 106. In other words, the duct liner 140 may encapsulate a portion of the coils 106 by extending 360 degrees about the interior surface 150 of the duct 102. In some embodiments, while the duct liner 140 be large enough to surround the downstream 112 portion of the coils 106, the duct liner 140 may be positioned entirely downstream 112 of the coils 106. Indeed, the duct liner 140 may be a tube or tubular in shape. As used herein, the term “tube” may refer to a shape having a hollow cross section such as a hollow section of a cone or pyramid, or a hollow cylinder or rectangular prism. In certain embodiments, the duct liner 140 may be a rectilinear tube and/or a curvilinear tube depending at least in part on the curvature of the interior surface 150 of the duct 102 and/or the airflow, as described above. In this manner, due at least in part to the continuous 360 degree perimeter of the duct liner 140, the duct liner 140 may be configured to collect condensate from the coils 106 whether the heat exchanger 100 is a horizontal right or a horizontal left heat exchanger 100. For example, as shown in the current embodiment, the heat exchanger 100 is positioned to function as a horizontal left heat exchanger 100. However, in certain embodiments, heat exchanger 100 may be rotated, or re-positioned, such that the heat exchanger 100 is positioned to function as a horizontal right heat exchanger 100. In such embodiments, when the heat exchanger 100 is rotated from a horizontal left to a horizontal right position, the drain pan 130 may be repositioned such that the condensate is configured to drop vertically 113 downward to the drain pan 130. However, in such embodiments, due at least in part to the tubular shape of the duct liner 140, the duct liner 140 be configured to function as intended whether the heat exchanger 100 is in a horizontal right or a horizontal left position without a change in position of the duct liner 140.

As mentioned above, in certain embodiments, the duct liner 140 may function as the drain pan 130 and replace the drain pan 130 such that the duct liner 140 extends from the drain 132 to downstream 112 of the coils 106. For example, as shown in FIG. 6, the duct liner 140 may extend from the drain 130 to approximately 12 to 18 inches downstream 112 of the coils 106. Further, as shown in FIG. 6, the duct liner 140 may be conical in shape. That is, the bottom surface 141 of the duct liner 140 may be disposed at the angle 143 relative to the horizontal plane 145 and the top surface 149 of the duct liner 140 may also be disposed at the angle 143 relative to the horizontal plane 145. In this manner, the heat exchanger 100 may be repositioned between a horizontal right position and a horizontal left position while the duct liner 140 remains in the same position. For example, as shown in the current embodiment, the heat exchanger 100 is positioned as a horizontal left heat exchanger 100 and the duct liner 140 is positioned to catch condensate as it falls vertically 113 downward. However, if the heat exchanger 100 is re-positioned as a horizontal right heat exchanger 100, the duct liner 140 is still in a suitable position to catch the condensate. Indeed, in some embodiments, the duct liner 140 may also be considered a drain pan configured to collect condensate and direct the condensate toward the drain 132. In such embodiments, the drain pan 130 may not be present.

In certain embodiments, the duct liner 140 may be adjustable, such that the duct liner 140 is configured to be placed within various sized ducts. For example, as shown in FIGS. 7 and 8, the duct liner 140 may include a split or separation 181 along the length 147 of the duct liner 140. Accordingly, a first flap 182 formed along a side of the split 180 may be configured to move, or slide, beneath a second flap 184 that is formed along the opposite side of the split 181. In this manner, an overlap distance 186 of the first flap 182 overlapping with the second flap 184 may be adjusted. As the overlap distance 186 is adjusted, a cross-sectional area 188 of the duct liner 140 may correspondingly adjust, or change. In some embodiments, once the cross-sectional area 188 has been adjusted according the duct 102 in which it is to be utilized, the split 181 may be sealed and/or joined, such as through caulking, welding, brazing, bolting, or any other suitable sealing/joining technique. In some embodiments, due at least in part to the adjustment of the cross-sectional area 188 of the duct liner 140, the lip 180 may be formed of a flexible material such that the lip 180 does not deform when the cross-sectional area 188 is adjusted. Further, in some embodiments, the lip 180 may be configured to deform, or corrugate, in conjunction with the adjustment of the cross-sectional area 188. Still further, in some embodiments, the lip 180 may be joined to the downstream end 152 of the duct liner 140 after the cross-sectional area 188 has been adjusted to the appropriate area.

Moreover, as discussed herein, the duct liner 140 may be any suitable shape, which may depend at least in part on the shape of the duct 102 and/or the airflow through the duct 102. Accordingly, as shown in FIG. 9, the duct liner 140 may be rectilinear in shape. In certain embodiments, the rectilinear duct liner 140 may include one or more splits 181 along the length 147 of the duct liner 140 to adjust the cross-sectional area 188 of the duct liner 140 as discussed above in reference to FIGS. 7 and 8.

Further, it should be noted that the duct liner 140, as discussed herein, may be applied to any suitable HVAC system 104, such as residential systems or commercial systems. Indeed, the duct liner 140 may be placed within existing and previously installed HVAC systems 104. However, in some embodiments, the HVAC system 104 may be manufactured with the duct liner 140. Moreover, it should be noted that the duct liner 140 may be formed of any suitable material such as rubber, plastic, metal, Teflon, or any other suitable material. In some embodiments, the material of the duct liner 140 may be corrosion-resistant and/or waterproof.

Accordingly, the present disclosure is directed to providing systems and methods for a duct liner configured to reduce an amount of condensate that is blown downstream of a drain pan to other portions of an HVAC system. Moreover, the curvature and size of the duct liner may substantially match the curvature and size of the duct in which it is disposed, thereby maintaining the airflow of the duct. Further, the duct liner may provide for thermal insulation between the air flowing through the duct and an external environment of the duct by providing an air gap disposed between the duct liner and an interior surface of the duct.

While only certain features and embodiments of the present disclosure have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures or pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the present disclosure. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode of carrying out the present disclosure, or those unrelated to enabling the claimed embodiments. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation. 

1. A heating and cooling system, comprising: a duct liner configured to be disposed within an air duct and at least partially downstream of a heat exchanger coil relative to a direction of airflow within the air duct, wherein the duct liner comprises a tube, and wherein the duct liner is configured to flow fluid from the heat exchanger coil toward a drain of the heating and cooling system.
 2. The heating and cooling system of claim 1, comprising a drain pan configured to collect the fluid and flow the fluid to the drain, wherein the drain pan is disposed within the air duct beneath the heat exchanger coil.
 3. The heating and cooling system of claim 2, wherein the duct liner is disposed vertically above the drain pan.
 4. The heating and cooling system of claim 2, wherein the duct liner is disposed at an angle relative to the drain pan to direct the fluid to the drain pain.
 5. The heating and cooling system of claim 1, wherein the duct liner substantially matches a curvature of an interior surface of the air duct.
 6. The heating and cooling system of claim 1, wherein the duct liner is a curvilinear tube.
 7. The heating and cooling system of claim 1, wherein the duct liner is a rectilinear tube.
 8. The heating and cooling system of claim 1, wherein the duct liner is conical.
 9. The heating and cooling system of claim 1, wherein the duct liner is cylindrical.
 10. The heating and cooling system of claim 1, wherein the duct liner comprises a lip extending radially inward from a downstream edge of the duct liner.
 11. The heating and cooling system of claim 1, wherein the duct liner is configured to encircle a downstream portion of the heat exchanger coil.
 12. The heating and cooling system of claim 1, comprising an evaporator, wherein the evaporator comprises the heat exchanger coil.
 13. The heating and cooling system of claim 1, wherein a cross-sectional area of the duct liner is adjustable.
 14. The heating and cooling system of claim 1, comprising an air gap disposed between the duct liner and the air duct.
 15. A heat exchanger system, comprising: an evaporator coil configured to condense a vapor within air flowing through the heat exchanger system; and a duct liner configured to encircle the evaporator coil and extend downstream of the evaporator coil, wherein the duct liner is configured to guide condensate from the vapor toward a drain of the heat exchanger system.
 16. The heat exchanger system of claim 15, comprising a drain pan, wherein the duct liner is disposed vertically above the drain pan.
 17. The heat exchanger system of claim 16, wherein the duct liner is sloped downward toward the drain pan.
 18. The heat exchanger system of claim 15, wherein the evaporator coil is configured to be disposed in a horizontal right heat exchanger configuration and a horizontal left heat exchanger configuration, and wherein duct liner is configured to encircle the evaporator coil in the horizontal right heat exchanger configuration and the horizontal left heat exchanger configuration in a common position within an air duct of the heat exchanger system.
 19. A heating and cooling system, comprising: a duct configured to flow air in a downstream direction, comprising: a heat exchanger coil; and a drain pan configured to surround the heat exchanger coil and configured to guide condensate from the air to a drain of the heating and cooling system.
 20. The heating and cooling system of claim 19, wherein the drain pan comprises a conical tube.
 21. The heating and cooling system of claim 19, wherein the drain pan extends approximately 12 to 18 inches downstream of the heat exchanger coil.
 22. The heating and cooling system of claim 19, wherein the drain pan comprises the drain, wherein the drain is configured to direct the condensate to a location external to the duct.
 23. The heating and cooling system of claim 19, wherein the drain pan comprises a separation along a length of the drain pan.
 24. The heating and cooling system of claim 19, wherein the drain pan comprises a lip extending radially inward from a downstream edge of the drain pan. 